Coxiella burnetii establishes a small cell variant (SCV)-like persistent form to survive adverse intracellular conditions.

Coxiella burnetii forms a small cell variant-like persistent form under hypoxia, increasing infectivity, antibiotic tolerance, and resistance to immune clearance.

• Why it matters: Understanding how C. burnetii persists inside host cells is crucial because chronic Q fever can develop months or years after infection without symptoms, yet little is known about its persistence mechanisms.
• What they did: Researchers infected primary murine macrophages with C. burnetii under normoxic and hypoxic conditions, observing that hypoxia induces an SCV-like form characterized by smaller size, condensed chromatin, and thicker cell wall.
• The result: The SCV-like form is more infectious, tolerant to antibiotics, and less susceptible to macrophage clearance, suggesting it enables bacterial survival and persistence during adverse conditions.